Current Status Of Water Quality And Health Risk Assessment Of Water Quality In Rural Shunyi In Beijing

Objective:To master the situation of rural supply facilities and water quality, to find existing problems, to evaluate the health risks of water quality, and to ensure the safety of drinking water in Shunyi district city, Beijing city.Methods:Using the survey method with questionnaire and interview to village cadre and waterworks responsible person, the basic situation of 355 rural waterworks are investigated in 365 villages of 19 towns in Shunyi district. According to the requirement of Beijing rural drinking water hygiene test items implementation plan in 2014 and 2015,312 water samples are analysed in 39 villages of 19 towns in Shunyi District. According to the water quality health risk assessment model provided by international cancer research organization (IARC), to analyse the health hazard effect of drinking water in rural areas of Shunyi District in 2015.Results:The number of water works which water supply capacity of 1000 tons or more a day in Shunyi rural is 90. The population who use the water supply accounts for 44.19% of the rural population in the survey. The type of water supply in the rural is groundwater, and 56.06% waterworks has a pollution source in the range of 30 meters.269 waterworks have disinfection equipment which accounting for 75.77% of the total. The number of waterworks which is completed of the pipe network update before 2013 is 337(94.93%). According to the city water quality standards, the overall qualified rate of rural drinking water is 68.27%. The qualified rate of general chemical and microbiological indexes of rural drinking water is higher than 95%. The qualified rate of main sensory indicators (e.g. chroma is 90.38%) and toxicological indicators (e.g. arsenic is 84.94%) is lower relatively. The qualified rate of wet season is slightly higher than dry season, but there is no significant difference(X2=0.370, P=0.543). The qualified rate of tap water is lower than the peripheral water, but there is no significant difference (X2=0.356, P=0.551). Water qualified rate of different water supply scale was not statistically significant (X2=0.266,P=0.966). Qualified rate of peripheral water of waterworks with pipe renewal is higher than that of waterworks without pipe renewal (X2=7.761, P=0.005). The qualified rate (76.92%) of the water quality of the waterworks with sanitary license is higher than that of the waterworks (62.04%) without sanitary license, the difference is statistically significant (X2=2.829, P=0.093). The individual annual risk of cadmium and chromium in all towns in Shunyi District is lower than 5×10-5 a-1 level, the risk of arsenic in 4 towns was higher than 5 × 10-5 a-1 level. The risk of body toxic substance is far below 5×10-5 a-1level. The risk of relatively high water fluoride is in 10-9 a-1 level.Conclusion:Most waterworks are single village water supply, the daily water supply of them is lower than 1000 tons in Shunyi district. More than half waterworks have pollutions source in 30 meters. The main indicators of drinking water quality are sensory index and toxicity index. The pipe renewal and sanitary license of waterworks are helpful to improve the qualified rate of drinking water in rural areas. Health risk assessment shows that there is health risk of arsenic in drinking water of individual towns.